Monza won a thrilling play-off against Pisa 4-3 to ensure top flight football for the first time in their history.
Serie A was the goal set by the 85-year-old ex-prime minister since he bought the club in 2018, a year after selling AC Milan, which he made a giant of European football during his 30 years of ownership.
Monza join Lecce and Cremonese, the two clubs directly promoted from Serie B at the end of the regular season.
Fourth in the championship, Monza had to go through the play-offs involving the teams that finished 3rd and 8th place.
The three promoted will take the top tier places from relegated Venezia, Genoa and Cagliari.
Monza was still in Serie C when Berlusconi bought the club from the Milan region in 2018 for a reported three millions euros ($3.4 million).
They moved up to Serie B in 2020, but last year missed out in the promotion play-offs, despite an aggressive transfer policy, marked in particular by the recruitment of big names like Kevin-Prince Boateng and Mario Balotelli.
Berlusconi, who entrusted the management of the club to his right-hand man from the Milanese years Adriano Galliani, 77, relied this season on players more experienced in Serie B.
Berlusconi’s period as owner of AC Milan saw them win five European Cups and eight Serie A titles.
He sold the club in 2017 to a consortium led by Chinese businessman Li Yonghong. American fund Elliott took over the following year after Li defaulted on a loan to buy the club.